The present invention relates to a method and apparatus for adjusting the quantity of water deposited on fine aggregate to be used for preparing mortar or concrete mixture.
Fine aggregate such as river or mountain sand are widely used to prepare mortar or concrete and thereby construct buildings or many other structures. As is well known, the fine aggregates are generally stored in the outdoor and often subjected to rain, dew or snow so that the water quantity deposited thereon varies greatly and can not be controlled.
When preparing mortar or concrete using the fine aggregate as well as a powder of hydraulic substance (e.g. cement) and water, it is essential to definitely determine various ratios of a resulting mixture, such as water to cement ratio (W/C) and cement to sand ratio (C/S), which ratios have a great influence upon the characteristics of the resulting mixture. However, these ratios cannot be determined unless the water quantity deposited on the surface of particles of fine aggregate to be actually used is exactly recognized.
U.S. Pat. No. 4,384,787 discloses a method and apparatus for adjusting the quantity of liquid adhered to fine particles wherein an impact force larger than the adhesive force of the liquid is applied to the particles. However, it was not definitely clarified how the quantity of liquid is separated from the particles by applying the impact force, thereby making it impossible to constantly obtain favorable results. Moreover, the use of an impact body with which the particles are intended to collide is continuously subjected to abrasion, whereby the impact body can not be used for a long period of time and therefore will frequently require mending and exchanging.